Climate Science Is Not Settled

We are very far from the knowledge needed to make good climate policy, writes leading scientist Steven E. Koonin

Steven E. Koonin

Sept. 19, 2014 12:19 p.m. ET

The idea that "Climate science is settled" runs through today's popular and policy discussions. Unfortunately, that claim is misguided. It has not only distorted our public and policy debates on issues related to energy, greenhouse-gas emissions and the environment. But it also has

inhibited the scientific and policy discussions that we need to have about our climate future.

The crucial scientific question for policy isn't whether the climate is changing. That is a settled matter: The climate has always changed and always will. Geological and historical records show the occurrence of major climate shifts, sometimes over only a few decades. We know, for instance, that during the 20th century the Earth's global average surface temperature rose 1.4 degrees Fahrenheit.